Discriminant analysis has been applied to organochlorine contaminant data from a small number (ca 3-25) of 12 different marine mammal species to discriminate between the species on the basis of the chlorobiphenyls (CB) patterns in blubber and account for the effects of age, sex, condition and location of the mammals. The raw data are normalised to a single congener, CB 153, to reduce the effects of life history and sex, after which the discriminant factors are plotted to display the differences between species in relation to the intake and the metabolism of chlorobiphenyls. An understanding of these differences gives a better knowledge of the relative sensibility of these species. The sperm whales were found to have the least ability to metabolise CBs when compared with other cetaceans, although the concentration range observed for total CB was relatively low (265-6,313 µg/kg lipid weight).